Pedro Martinez is on the disabled list. Tom Glavine has been out after a recent blood clot scare. Orlando Hernandez won’t make his next turn in the rotation because of a tired arm.

So although the Mets don’t expect Dave Williams to win the pennant for them, with the spate of injuries the team has faced, outings like last night’s have become more important.

And though Williams will never be mistaken for Martinez, whose recently strained right calf forced Williams’ call-up, the left-hander was very effective last night in the Mets’ 6-2 win over St. Louis last night at Shea. He earned his first big league victory since May 7.

“This is what they brought me here to do,” Williams (3-3) said. “The offense is going to score runs, so I just have to keep us in the game.”

Williams lasted 6 1/3 innings before tiring and being removed for Roberto Hernandez after pinch hitter Scott Spiezio doubled to right, the Cardinals’ second hit of the inning.

Hernandez provided terrific relief, getting out of that jam by getting the next two batters and retiring the side in order in the eighth, allowing the Mets to hold their three-run lead.

Williams was acquired in May in a trade from the Reds after a wildly inconsistent start to the season in Cincinnati. He managed to toss a couple of solid outings with the Reds, but was 2-3 a 7.20 ERA before being sent to the minors and then shipped to the Mets, when he went to Triple-A Norfolk.

“I was on the [disabled list] and they sent me down to St. Lucie to straighten some things out,” said Williams, who had suffered a strained shoulder. “In Cincinnati, I was 80 percent, now I feel I’m 100 percent.”